Solution 1: AddUnique Indexon your table: ALTERIGNORETABLE`TableA`ADDUNIQUEINDEX (`member_id`, `quiz_num`, `question_num`, `answer_num`); Solution 2: Add primry key in your table then you can easily remove duplicates from your table using below query: DELETEFROMmemberWHEREidIN(SELECT*FR...
SELECT DISTINCT column1, column2, ... FROM original_table; TRUNCATE original_table; RENAME TABLE new_table TO original_table; END // DELIMITER ; 您可以通过调用存储过程来执行此操作: CALL remove_duplicates(); 这将创建一个新表new_table,将不重复的记录插入到该表中,然后清空原始表original_table,...
DELIMITER // CREATE PROCEDURE remove_duplicates() BEGIN -- 删除重复数据 DELETE t1 FROM table_name t1 JOIN table_name t2 WHERE t1.id > t2.id AND t1.column1 = t2.column1 AND t1.column2 = t2.column2; -- 创建唯一索引 CREATE UNIQUE INDEX index_name ON table_name (column1, column2,...
END IF; DELETE FROM students_with_duplicates WHERE id = @id AND id NOT IN (SELECT id FROM (SELECT id FROM students_with_duplicates) AS temp); END LOOP; CLOSE cur; END // DELIMITER ; 接下来,我们可以调用这个存储过程来删除重复记录: CALL remove_duplicates(); 问题与解答: 1、Q:DISTINCT关...
Patrick Kelly February 08, 2006 09:38PM Re: Need to removet duplicates from one table Bob Field February 08, 2006 10:17PM Re: Need to remove duplicates from one table Patrick Kelly February 09, 2006 07:09AM Sorry, you can't reply to this topic. It has been closed.Content...
SELECTidFROMtable1UNIONSELECTidFROMtable2; 1. 2. 3. 序列图 以下是查询过程的序列图: Resulttable2table1Resulttable2table1SELECT idSELECT idUNIONRemove duplicatesReturn unique ids 解释 首先,我们从table1中选择id字段。 然后,我们从table2中选择id字段。
MySQL的工具--创建测试表 if object_id('test') is not null drop table test create table ...
DELIMITER//CREATEPROCEDUREsplit_and_remove_duplicates()BEGINSELECTDISTINCTSUBSTRING_INDEX(SUBSTRING_INDEX(data,',',numbers.n),',',-1)dataFROMtest_tableJOINnumbersONCHAR_LENGTH(data)-CHAR_LENGTH(REPLACE(data,',',''))>=n-1GROUPBYdata;END// ...
换出时将autoincrement保存在全局的的映射表中,然后淘汰内存中的dict_table_t。换入时通过查找全局映射表恢复到dict_table_t结构体中。相关的函数为dict_table_add_to_cache及dict_table_remove_from_cache_low。 (2) row_import, table truncate过程更新autoincrement。 (3) handler首次open的时候,会查询当前表...
I have 2 tables, as all the data seems too large for one (got error on import). I am trying to find if data (let's say rows) duplicate in Table 1 first and remove them. Then I want to see if Table 2 duplicates any of Table 1's rows and remove them from Table 2. Then I ...